[ltt-dev] UST - Problems in recording trace on a current process

[pierre-marc.fournier@polymtl.ca (Pierre-Marc Fournier)]

On February 9, 2010 11:43:24 Naren wrote:
> Hi ,
>
> As Douglas mentioned, there were problems with rcu library installation. So
> i uninstalled libkcopat, rcu and ust. Got the latest builds of libkcompat,
> userspace-rcu and ust from git and installed them again in the above
> mentioned order.
>
> I am getting this error
>
> *root at naren-laptop:/tmp# ustctl --list-markers 23444*
> *ustctl[23462/23462]: Error: connect: No such file or directory (in
> ustcomm_connect_path() at ../libustcomm/ustcomm.c:452)*
> *ustcmd_send_cmd: could not connect to PID 23444*
> *error while trying to list markers for PID 23444*
> *root at naren-laptop:/tmp# *
> *
> *
> I guess this is same error Soumya is getting.
>

Looks like it. Please make sure:
- The program you are trying to trace still exists when you run ustctl
- The program you are trying to trace is linked to libust

Look in /tmp/ust-app-socks if a socket for this pid is created there when you 
start the program. If it's there, run ustctl in strace and send us the output 
near the connect() call so we can see what file it's trying to open.

I doubt this has something to do with permissions, as the error would not 
be "No such file or directory".

You might also want to configure ust with the command

CFLAGS="-DUST_DEBUG" ./configure

in order to enable additional debugging output.

pmf